Process for the attachment of hour signs on time piece dials

ABSTRACT

The hour signs for a timepiece are placed on a support with their feet upwards. A dial is placed face down on the feet, the dial being of softer material than the feet, and stamped so that the feet cut-out their own fixing holes. Each foot preferably has a central hole into which a cut-out portion of the dial is forced.

United States Patent [191 111 3,798,730 Morf Mar. 26, 1974 [54] PROCESS FOR THE ATTACHMENT OF 2,955,351 10/1960 McCreadie 29/432 X I HOUR SIGNS ON TIME PIECE DIALS 3.047942 8/1962 Schneider et al.. 29/177 X 3,276,112 10/1966 Tantlmger et al. 29/432 [76] Inventor: Victor Morf, Pierre Grise 7, La

chaux-de-Fonde Switzerland 2300 FOREIGN PATENTS OR APPLICATIONS [22] Flledl Apr. 17, 1972 393.191 2/1965 Switzerland 29/177 955,813 4 1964 G 't B 't 29/432 21 Appl. No.: 244,593 am Related Apphcauon Data Primary Examiner-Charles W. Lanham [63] Continuation-impart of Ser. No. 882,853, Dec. 8, Assistant Examiner A Dipalma L969 abandoned Attorney, Agent, or FirmRobert E. Burns; EmmanlJ. L b t [30] Foreign Application Priority Data ue o a 0 Dec. 10, 1968 Switzerland 18402/68 52 us. Cl 29/177, 29/432, 29/509, [57] ABSTRACT 29/522 58/127 1 13/1 16 FF The hour signs for a timepiece are placed on a support 1 llgtr their feet upwards A is placed face down on [58] held of Search 29/177 the feet, the dial being of softer material than the feet, 113/116 1 58/127 and stamped so that the feet cut-out their own fixing holes. Each foot preferably has a central hole into [56] References C'ted which a cut-out portion of the dial is forced.

UNITED STATES PATENTS 1.434,838 11/1922 Oedell v. 58/104 13 Claims, 5 Drawing Figures PATENTEDMARZB I974 SHEET 1 [IF 2 PROCESS FOR THE ATTACHMENT OF HOUR SIGNS ON TIME PIECE DIALS This application is a continuation-in-part of my application Ser. No. 882,853 filed Dec. 8, 1969, now abandoned.

The present invention concerns a process for fixing metal elements provided with fastening pins on a sup- -port plate and in particularly to securing hour signs on dials of timepieces.

The attachment of fitted hour signs known as applique, on metal horological dials has heretofore presented considerable difficulty and disadvantages. In order to present an attractive appearance, the dials must have a high quality surface finish. If the hour signs are applied before the dial is given its final finish, it is difficult to finish the dial in the corners around the raised hour signs. Moreover the finish desired on the dial is usually different from that of the hour signs so that it is difficult to finish one without spoiling the other. If the hour signs are applied after the dial has been given its final surface finish, it is difficult to attach the hour signs to the dial without marring the surface finish of the dial. It has been proposed to provide pins of the backs of the hour signs but this has a major drawback in that it is necessary to make holes in the dial into which pins of the signs are placed. In order to overcome this drawback other methods of fixing such as soldering or sticking with adhesive are available. However, the heat required for soldering is likely to spoil the finish of adjacent portions of the dial. Moreover soldering is not applicable when the finishing of the dial includes the application of a coat of varnish. Adhesive is not sufficiently dependable as an attaching means and moreover portions of the adhesive are likely to be extruded around the edges of the signs.

It has also been proposed to make a cold penetration of the pins into the dial without first making recesses for the pins in the dial by utilizing plastic dial plates which allow such a penetration. However this mode of attachment has not been applicable to metal dials which are used in better quality watches.

The aim of the present invention is to provide a fastening for metal elements in a supporting plate, particularly for attaching hourmarkers on a metal dial plate, which retains the pins, the advantages being due to, particularly, a purely mechanical and rigid fixing, thereby obviating the need to make holes in the plate beforehand, and which can be as satisfactory in metal as in plastic material.

The process according to the invention is characterized in that the metal elements are made of much harderma'terial than theplate and that the elements are fixed to the'plate by means of stamping, the pinacting as part of the means of stamping and cutting its own hole in the manner of a punch.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic view showing the time-piece hour sign at the beginning of the fixing operation on a dial.

FIG. 2 shows the sign at the end of the fixing operation.

FIGS. 3 and 4 are views similar to FIGS. 1 and 2 respectively but showing the attachment of an hour sign with a solid pin of non-circular cross section, and

FIG. 5 is a section on the line 5-5 in FIG. 4.

The drawings show a portion of a metal timepiece dial 1 on which it is desired to attach an hour sign 2 by its pin 3. Prior to the attachment of the hour signs, the dial is given its final surface finish. For example a copper dial is polished and then satinized by means of a steel brush. The dial is then electrolitically plated with silver or gold and finally given a coating of transparent cellulosic varnish. An aluminum dial is polished and then electrolytically oxidized to provide a colored anodized surface. A coating of clear varnish may then be applied if desired. The sign is of a metal harder than that of dial 1 and the pin 3 has sharp edges. The hardness of the signs expressed in terms of the Rockwell scale should be at least twice that of the dial. For example if the dial is formed of copper or aluminum having a Rockwell hardness of 15 to 20, the signs may be formed entirely of brass with a Rockwell hardness of approximately 50. If the hour sign is made of 18 carat gold, the hardness of the pin is about 60 Rockwell. Preferably the entire set of the signs to be fixed on the dial plate are placed on a support 4 which serves as means for positioning and laterally guiding the markers. Dial l is then placed on pins 3 which are successively positioned in alignment with a drift 5, comprising bore 6, having sharp edges, and a centrally punch portion 7, this drift being similar to drifts used for punching out washers.

The signs each have an axial blind hole 8 in its pin 3, the diameter of hole 8 being slightly less than the diameters of punch portion 7. The foot 3 has a height approximately double the thickness of the clial plate but this portion can vary in relation to the materials to be fitted together.

When the drift 5 and its punch 7 hit the reverse side of the dial 1, the pin 3 acts as a counterpunch and cuts its own fixing hole 9 in the dial plate, and cutting a washer 10 which, in this particular case, is regarded as waste. The central part... 11 of the cut out washer is driven by the punch portion 7 into hole 8 of the pin. As the diameter of the punch 7 is slightly greater than the diameter of the hole 8, the punch 7 and the hole 8 cut out, as is known, a section shaped as a slightly truncated cone which is forced into the hole 8 and provides a high pressure on the walls thereof, thereby improving attachment of the sign.

In the case of time-pieces of small dimensions, such as Wristwatches, it is not generally practical to provide a hole in the pins of the signs but the fastening will nevertheless be sufficiently rigid. In this case, the crosssection of the pin or pins can be other than circular in order to prevent the marker turning during a later facetting operation on the signs.

The attachment of hour signs to wristwatch dials by means of a solid pin of non-circular cross section provided on each sign is illustrated schematically in FIG. 3 to 5. Before attachment of the hour signs, the dial is given its final surface finish, for example as described above. The method of attachment of the hour signs is the same as described with reference to FIG. 1 and 2 except that the hour sign 2 is provided with a pin 3 which is of non-circular cross-section and does not have an axial hole. In FIG. 5 the pin 3 is shown by way of example as being hexagonal. However it may be of other non-circular cross section, for example square or round with a flat side, to prevent rotation of the pin in the hole it punches in the dial. The sign 2, or at least the pin 3, is of harder meta] than the dial as described above and the pin is squared-ended with sharp peripheral edges so as to cut cleanly through the dial without causing any denting or distortion that would show on the face of the dial. The length of the pin 3 is slightly greater than the thickness of the dial. For example, the length of the pin may exceed the thickness of the dial by 2 or 3 hundredths of a millimeter. After the pin 3 has punched a hole in the dial 1 as shown in FIG. 4, the punch 7 is brought down and acts through the cut-out slug 8 to upset or flatten the pin 3 so as to secure the pin still more solidly in the hole in the dial.

It is possible to attach the signs one by one or to attach all of the signs simultaneously by means of a stamping tool comprising several drifts.

The signs may or may not be facetted beforehand. As the visible surface of the dial is not touched during the operation, it can be finished and varnished beforehand as described above.

The sole limiting condition of this process is that the material of the sign must be substantially harder than that of the dial plate.

This process is equally applicable for mounting of bottom plates of pillars intended to carry bridges.

What I claim is:

1. In a process of manufacturing a time piece dial, the steps of providing a metal dial plate having front and rear faces, finishing the front face of said dial plate to provide a final finish thereon, providing at least one metal hour sign piece comprising a body protion having an under face adapted to engage said front face of the dial plate and at least one pin projecting from said under face ofthe body portion and spaced inwardly from the edges of said body portion, said pin being substantially harder than said dial plate and having an end with sharp end edges, positioning said sign piece on a support with said pin up, positioning said dial plate over said sign piece with said finished front face down, engaging the rear face of said dial plate with a tool having a sharp edged bore in alignment with said pin and corresponding in shape and size to said pin and forcing said tool toward said support to force said pin through said dial plate and thereby punching a hole in said dial plate tightly to receive said pin, and to bring said under face of the body portion of said sign piece into engagement with an area of the finished front face of said dial surrounding said hole and covering the edges of the hole.

2. A process according to claim 1 wherein the hardness of at least the pin portion of said sign piece is at least twice the hardness of the dial plate expressed in terms of Rockwell hardness.

3. A process according to claim 2, wherein the dial plate has a Rockwell hardness of the order of 15 to 20 and the sign has a Rockwell hardness of the order of 50 to 60.

4. A process according to claim 1, wherein said pin portion of said sign piece is of non-circular cross section.

5. A process according to claim 1, wherein a plurality of said sign pieces to be attached to a single dial plate are positioned on said support in the position relative to one another that they are to have on said dial plate and are attached to said dial plate simultaneously, said tool having a bore in alignment with each pin of said sign pieces.

6. A process according to claim 1, wherein the length of said pin exceeds the thickness of said dial plate by about 2 or 3 hundredths of a millimeter.

7. A process according to claim 1, further comprising the step of upsetting said pin after the under face of the body portion of said sign piece has been brought into engagement with the finished front face of the dial plate.

8. A process according to claim 1, wherein a central hole is provided in each said pin and a central punch is provided in each bore of said tool to force a cut-out portion of said dial plate into said central hole of the pin.

9. A process for fixing metal elements onto a plate comprising providing each of said elements with at least one fixing pin of a material substantially harder than that of said plate and having a central bore, placing said elements on a support with the pins facing upwardly, placing said plate on said pins and striking the reverse side of said plate with a tool having a hole the outer periphery of which corresponds to and is in line with the outer periphery of each said pin and a central punch provided in said hole of said tool in line with the said central bore of said pin so that each pin acts as a punch to cut out its own fixing hole in said plate and said central punch forces a cut-out portion of said plate into said central bore of each said pin.

10. A process according to claim 9, wherein said central punch is of larger cross section than said central bore in each said pin whereby said pin is expanded in the hole cut out in said plate.

11. A process according to claim 9, wherein said pins are of a height approximately two times the thickness of said plate.

12. A process according to claim 9, wherein said plate is a time-piece dial and said elements are hour signs.

13. A process according to claim 9, wherein said plate is a bottom plate and said elements are pillars. 

1. In a process of manufacturing a time piece dial, the steps of providing a metal dial plate having front and rear faces, finishing the front face of said dial plate to provide a final finish thereon, providing at least one metal hour sign piece comprising a body protion having an under face adapted to engage said front face of the dial plate and at least one pin projecting from said under face of the body portion and spaced inwardly from the edges of said body portion, said pin being substantially harder than said dial plate and having an end with sharp end edges, positioning said sign piece on a support with said pin up, positioning said dial plate over said sign piece with said finished front face down, engaging the rear face of said dial plate with a tool having a sharp edged bore in alignment with said pin and corresponding in shape and size to said pin and forcing said tool toward said support to force said pin through said dial plate and thereby punching a hole in said dial plate tightly to receive said pin, and to bring said under face of the body portion of said sign piece into engagement with an area of the finished front face of said dial surrounding said hole and covering the edges of the hole.
 2. A process according to claim 1 wherein the hardness of at least the pin portion of said sign piece is at least twice the hardness of the dial plate expressed in terms of Rockwell hardness.
 3. A process according to claim 2, wherein the dial plate has a Rockwell hardness of the order of 15 to 20 and the sign has a Rockwell hardness of the order of 50 to
 60. 4. A process according to claim 1, wherein said pin portion of said sign piece is of non-circular cross section.
 5. A process according to claim 1, wherein a plurality of said sign pieces to be attached to a single dial plate are positioned on said support in the position relative to one another that they are to have on said dial plate and are attached to said dial plate simultaneously, said tool having a bore in alignment with each pin of said sign pieces.
 6. A process according to claim 1, wherein the length of said pin exceeds the thickness of said dial plate by about 2 or 3 hundredths of a millimeter.
 7. A process according to claim 1, further comprising the step of upsetting said pin after the under face of the body portion of said sign piece has been brought into engagement with the finished front face of the dial plate.
 8. A process according to claim 1, wherein a central hole is provided in each said pin and a central punch is provided in each bore of said tool to force a cut-out portion of said dial plate into said central hole of the pin.
 9. A process for fixing metal elements onto a plate comprising providing each of said elements with at least one fixing pin of a material substaNtially harder than that of said plate and having a central bore, placing said elements on a support with the pins facing upwardly, placing said plate on said pins and striking the reverse side of said plate with a tool having a hole the outer periphery of which corresponds to and is in line with the outer periphery of each said pin and a central punch provided in said hole of said tool in line with the said central bore of said pin so that each pin acts as a punch to cut out its own fixing hole in said plate and said central punch forces a cut-out portion of said plate into said central bore of each said pin.
 10. A process according to claim 9, wherein said central punch is of larger cross section than said central bore in each said pin whereby said pin is expanded in the hole cut out in said plate.
 11. A process according to claim 9, wherein said pins are of a height approximately two times the thickness of said plate.
 12. A process according to claim 9, wherein said plate is a time-piece dial and said elements are hour signs.
 13. A process according to claim 9, wherein said plate is a bottom plate and said elements are pillars. 